UK-POLOS.NET - THE VW Polo Forum

Hi, just wondered if anyone could help.
My gf was driving her 96 Polo 1.9 Diesel and she said there was steam coming from engine, so she pulled over and the battery was boiling and evapourating the water, she went to a garage who had quick look and topped up the battery cells again and she drove back to her uni house. The garage guy reakons needs new alternator and maybe a battery.
Before I go and buy an alternator thought ask you guys for an opinion or if its happend to anyone else.
I havent seen the car as its at her uni but i'm thinking maybe its a fuse or wiring. I can't believe that it would be the alternator going wrong by oversupplying the battery,
well any help appreciated
matt.p

hello mate-

the alternator produces ac voltage but has a bult in regulator rectifier,this converts the output to dc volts and also regulates the power output so it does not overcharge the battery and other electrical components.

a simple charge rate test would confirm this.it should be between 13.5-15 volts....some say 14.5 is the safe max charge rate for a car.if it is above this then replace the alternator.you will also need to replace the battery as it will be more than likely gubbed.



william